Azo dyes containing the benzonaphthofuranol nucleus



AZO DYES CONTAINING THE BENZONAPHTHO- FOL NUCLEUS Robert S. Long and Bennett G. Buell, Bound Brook, NJ., assignors to American Cyanamid Company, New York, N.Y., a corporation of Maine No Drawing. Application March 8, 1957 Serial No. 644,732

Claims. (Cl. 260-152) 'This invention relates to azo dyes containing as the :residue of a coupling component a substituted alphabenzonaphthofuran having the following formula which R and R may be hydrogen and lower alkyl; :and R may be hydrogen, carboxy, or RNHCO-- wherein R represents the residue of a mononuclear aromatic lcarbocyclic primary amine. zfuran ring which is sometimes known as alpha-brazan is znormally numbered as follows This numbering and mqmenclature will be used through- :out the specification and claims The compounds of the present invention may be conzsidered-to have the following formula lRaO HO- O The alpha-benzonaphtho- 2,893,986 Patented July 7, 19 59 This compound is itself a coupling gomponent and azo dyes may be prepared from it. However, still more important shades may be obtained alkylation under conditions which normally alkylate alpha hydroxynaphthalenes to produce S-alkoxy-9-hydroxy-alpha-benzonaph thofurans. These also are good coupling components and can be used as such or can be further carbonated by the Kolbe reaction to produce 5-alkoxy-9-hydroxy-8- carboXy-alpha-benzonaphthofurans, which in turn can be transformed into their arylides by conventional reactions. The arylides form excellent ice-color coupling components which couple with the ordinary diazotized fast bases. In the case of these compounds the coupling takes place at the 10 carbon atom. Instead of first preparing the dihydroxy-alpha-benzonaphthofuran it is also possible to start with a resorcinol monoether in which the hydrogen of one of the Z-hydroxyl groups is replaced by a lower alkyl group such as methyl, ethyl, propyl, isopropyl, butyl, amyl, and the like. This results in producing a S-hydrOXy benzonaphthofuran which couples in the 6 position. For this reason the azo group in the typed formula for the dyes above is shown as going into the center of the ring system signifying that the coupling may be either on the benzene ring or on the naphthalene ring depending on the nature of the R and R radicals.

The dyes of the present invention and particularly those having a S-carboxyarylide are'desirable deep shades such as various tints of brown.

Alkylation of the 5,9-dihydroxybenzonaphthofuran may be carried out by heating the compound with the desired alcohol in the presence of sulfuric acid: any of the lower 7 alkanols may be used such as methanol, ethanol, propanol,

iso-propanol, butanol, iso-butanol, or any of the amyl alcohols. This alkylation procedure produces the 5-alkoxy-9-hydroxy-alpha-benzonaphthofuran and compounds of this type when coupled with diazotized fast bases couple into the benzene ring rather than the naphthalene ring. The ease with which coupling takes place is a very important property of the dyes of the present invention. There are no hydroxy groups ortho or para to the hydroxy group which directs the coupling and there is no danger of attacking the diazonium salt itself.

The invention will be illustrated in greater detail in conjunction with the following specific examples. The parts are by weight unless otherwise specified.

Example 1 A solution of 60 parts of naphthoquinone in 400 parts of acetic acid is added to a solution of 34.5 parts of resorcinol in 150 parts of acetic acid. To the resulting mixture at 50 C. is added about 3 parts of 50% sulfuric acid. The mixture is slowly heated to reflux and held at reflux until the reaction is substantially complete. The reaction mixture is then allowed to cool and after clarifying, it necessary, it is drowned in water. The solid product is isolated by filtration and washing, and dried at C. For purification, the product is then dissolved in parts of dry pyridine and 200 parts of dry benzene. 94 parts of acetic anhydride is added and the mixture is stirred at reflux until acylation is complete. The

mixture. is then cooled and the diacetylated product is isolated by filtration and washed with benzene and petroleum ether. The cake is dried at 70 C. and slurried in 600 parts of methanol. The mixture is heated to the boil and 166 parts of 20% sodium hydroxide solution is added. The mixture is stirred and heated until a clear solution is obtained. It is then cooled and added to a solution of 160 parts of concentrated hydrochloric acid in 500 parts of 50% aqueous ethanol. The white curdy product is isolated by filtration, washed with water, and dried. It is shown by analysis and 'by quantitative acetylation to be a pure dihydroxy compound. It analyzes correctly and has a melting point of 215-217" C.

Example 2 The product of Example 1 is padded on pieces of cotton cloth which are then immersed in baths containing various diazotized amines. The dyed cloths are observed to have the following shades:

A mixture of 7 parts of the product of Example 1, 7 parts of anhydrous methanol and 2.8 parts of concentrated sulfuric acid is heated at a slight positive pressure at 125 C. until the reaction is substantially complete.-

A substantial solidification of the reaction mixtureoc- I ours and the reaction mixture is therefore diluted with about 150 parts of water.

Twenty-two parts of 20% sodium hydroxide solution is then added. The product is salted to precipitate the sodium salt. This is filtered, washed with brine, and then taken up in 200 parts of water containing a smaller amount of sodium hydroxide.

- The mixture is heated to effect complete solution and acetic acid is the n added gradually to precipitate the free hydroxy compound. The light gray precipitate is filtered, washed, and dried. The crude product is then recrystallized from methanol and water producing a product of good purity.

The procedure ofthe above example is repeated replacing methanol with an equivalent amount of ethanol. The process proceeds smoothly and the corresponding S-ethoxy derivative is obtained. In a similar manner the process is repeated respectively with propanol, iso-propanol, butanol and amyl alcohol, in each case the reaction proceeds smoothly and the corresponding 5-ethoxy, S-propoxy, 5 isopropoxy, S-butoxy, and S-amyloxy derivatives result.

Example 4 The products of Example 3 are impregnated on pieces of cloth and then immersed in solutions of the following diazotized amines, the colors produced being as designated.

2-methoxy-4- nitroaniline Tan 3,3 -dimethoxybenzidine Light brown 2- aminoanthraquinone Dull tan 2,5-dichloroaniline Yellow brown Z-methoxy-S-nitroaniline Tan Z-naphthylamine Yellow brown 1-naphthylamine Brown 4 Example 5 A mixture of 10 parts of the products of Example '3, 60 parts of anhydrous potassium carbonate, and 60 parts of inert substance, such as .glass beads or sand, is agitated at -160165 C. under about 300 psi. pressure of carbon dioxide until carbonation is substantially complete. The product is isolated by leaching out with aqueous alkali followed by acidification of the solution. It is a gray solid of melting point 242-245 C. 'Further purification is elfected by 'salting out the sodium salt from strongly alkaline solution followed by acidification of the precipitate to form the free acid. The crude product obtained is not 100% the isomer represented by the formula. It appears tobe contaminated by small amounts of aproduct whichhassuch close properties that it is most probably the isomer in which the carboxy group is attached to the 10 carbon atom. The amount'of contaminant is insuflicient to have any significant effect on the dyestuffs prepared from the coupling component.

Example 6 OCH,

. xylene producing light yellow crystals'having a somewhat higher melting point.

Example 7 The product of Example 6 ispadded on pieces of cloth and the latter are then immersed in solutions of diazotized amines, with the following results Five parts of m-methoxyphenol and 6.8 parts of alphanaphthoquinone are dissolved in 40 parts of glacial acetic acid and 1.5 part of lzl-sulfuric acid is added. The solution is heated at reflux until the reaction is complete. It is then cooled'and drowned in 500 parts of a mixture of ice and water. The solid is filtered ofi, washed with water and dried in vacuo. The crude product melts at 7592 C.

Extimpie The products from Example 8 are used as a coupling component to form azo dyes with the following diazotized amines. The colors obtained are shown.

p-Nitroaniline Olive-gray o-Methoxy-p-nitroaniline Gray p-Chloraniline Red-brown This application is in part a continuation of our copending application Serial No. 414,866, filed March 8, 1954.

We claim:

1. Azoic coloring matters having the following formula Ar-N N in which R and R are selected from the group consisting of hydrogen and the lower alkyl radicals and R is selected from the group consisting of hydrogen, carboxy, and RNHCO- wherein R is the residue of a mononuclear aromatic carbocyclic primary amine, and Ar is the residue of a diazotized aromatic carbocyclic primary amine having a residual cyclic structure selected from those of the group consisting of benzene, naphthalene, diphenyl and anthraquinone.

2. Azoic coloring matters having the following formula MO 0 o OAlk no \0/ l in which Ar is the residue of a diazotized aromatic carbocyclic primary amine having a cyclic structure selected from those of the group consisting of benzene, naphthalene, diphenyl and anthraquinone, Alk is lower alkyl and M is a cation selected from the group consisting of hydrogen and the alkali metals.

3. Azoic coloring matters having the formula MO 0 O 0 CH3 in which Ar is the residue of a diazotized aromatic carbocyclic primary amine having a cyclic structure selected from those of the group consisting of benzene, naphthalene, diphenyl and anthraquinone and M is a cation se- ,e M. lected' from the group consisting 'or hydrogen and' the alkali metals.

4. Azoiccoloring matters having the following formula in which Ar is the residue of a diazotized aromatic carbocyclic primary amine having a cyclic structure selected from those of the group consisting of benzene, naphthalene, diphenyl and anthraquinone, R is a residue of a mononuclear aromatic carbocyclic primary amine and Alk is lower alkyl.

5. Azoic coloring matters having the following formula in which Ar is the residue of a diazotized aromatic carbocyclic primary amine having a cyclic structure selected from those of the group consisting of benzene, naphthalene, diphenyl and anthraquinone, and R is residue of a mononuclear aromatic carbocyclic primary amine.

6. Azoic coloring matters having the following formula oiQ-NHO 0 in which Ar is the residue of a diazotized aromatic carbocyclic primary amine having a cyclic structure selected from those of the group consisting of benzene, naphthalene, diphenyl and anthraquinone and in which Alk is lower alkyl.

7. Azoic coloring matters having the following formula.

OCHg

in which Ar is the residue of a diazotized aromatic carb'o cyclic primary amine having a cyclic structure selected? from those of the group consisting of benzene, naphtha-- lene, diphenyl and anthraquinone.

8. An azoic coloring matter having the following formula 2,893,986 7 8 9. An azoic coloringmatter having tha following fob 10. An az ic color g matter having the following mula formula References Cited in the file of this patent UNITED STATES PATENTS 15 1,936,926 Zahn etal N0v.28,1933 2,496,255 Glahn Jan.31,-1 950 

1. AZOIC COLORING MATTERS HAVING THE FOLLOWING FORMULA 